The present invention relates to a data storage tape cartridge. More particularly, it relates to a data storage tape cartridge configured to allow a single insertion orientation within a holding device, such as a tape drive.
Data storage tape cartridges have been used for decades in the computer, audio and video fields. While other forms of media storage, such as disk cartridges, are also available, the data storage tape cartridge continues to be an extremely popular form of recording large volumes of information for subsequent retrieval and use.
The data storage tape cartridge generally consists of an outer shell or housing maintaining at least one tape reel and a length of magnetic storage tape within an available internal area defined by the housing. The storage tape is wrapped about a hub portion of the tape reel and is driven through a defined tape path by a driving system. The housing normally includes a separate cover and base, the combination of which creates an opening (or window) of some type for allowing access to the storage tape by a read/write head upon insertion of the data storage tape cartridge into a tape drive. This interaction between storage tape and head may take place within the housing (for example, a mid tape load design), or the storage tape may be directed away from the housing to an adjacent area at which the read/write head is located (for example, a helical drive design or a leader block design). Where the tape cartridge/drive system is designed to direct the storage tape away from the housing, such as with a leader block design, a single tape reel configuration is normally employed. Conversely, where the tape cartridge/drive system is designed to provide head-storage tape interaction within or very near the housing, two tape reels are typically utilized.
With the two-tape reel design, a distinct tape path must be generated within the housing such that the storage tape is positioned parallel to a plane of the cartridge window for acceptable head engagement. This orientation is typically accomplished by providing various tape guides within the housing. The storage tape extends from one of the tape reels, along the tape guides, to the other tape reel. Obviously, the two tape reels and tape guides, as well as other components (such as, for example, a write-protection mechanism), occupy a portion of the available internal area within the housing. This reduction in the available internal area is directly converse to a desired objective of maximizing the amount of storage tape maintained by the data storage tape cartridge. Tape drives are normally sized to receive a "standard" sized data storage tape cartridge. Therefore, the size of the housing, and thus the available internal area within the housing, is normally fixed. The storage capacity of the data storage tape cartridge is directly related to the amount, or length, of the storage tape. The length of the storage tape, in turn, is directly related to the available internal area of the housing. Stated in most general terms, a reduction in the available internal area of the housing likewise reduces the amount of storage tape. Thus, any unnecessary components or other features of the data storage tape cartridge will directly impact the overall storage capacity, as a lesser amount of storage tape can be used.
One such feature sometimes considered is a means to prevent misinsertion of the data storage tape cartridge. As previously described, the tape drive is typically of a standard size. For example, 5.25 inch (130 mm) form factor and 3.5 inch (90 mm) form factor tape drives are commonly available. Importantly, regardless of particular size, the tape drive normally does not include any means for preventing improper insertion of the tape cartridge. In other words, with the standard tape drive design, it is quite possible for a user to insert the tape cartridge upside down or backwards. In either case, when the read/write head attempts to engage an improperly inserted tape cartridge, significant damage to the head can occur.
Attempts have been made in other related industries to deal with the above-described problem of cartridge misinsertion. For example, U.S. Pat. No. 5,694,178 to Sumner describes a magnetic disk cartridge having two keying slots sized to mate with extensions in the disk drive. These slots run the entire length of the Sumner disk cartridge. Because the magnetic disk media maintained by the Sumner cartridge has an extremely limited thickness, use of keying slots does not in any way impact the internal area available for maintaining the magnetic disk. In other words, because the Sumner cartridge maintains a thin media, Sumner is unconcerned with limiting any reduction in the available internal area of the cartridge through the use of keying slots. Further, because the Sumner cartridge does not make use of tape guides, no consideration is given to the impact the keying slots may have on tape guide location.
A directly opposite concern is presented by a data storage tape cartridge utilizing two tape reels and various tape guides. Any modification of the standard data storage tape cartridge configuration must account for reduction in the available internal area of the housing, and the resulting reduction in the amount of storage tape maintained therein. Additionally, the effect on tape guide(s) location must also be considered.
Data storage tape cartridges are important tools used to maintain vast amounts of information. However, with increasing complex reading/writing and magnetic tape technology, design of the data storage tape cartridge must evolve to provide for the prevention of misinsertion within a tape drive, while minimizing the effect, if any, upon the available internal area of the tape cartridge housing. Therefore, a need exists for a data storage tape cartridge designed to prevent misinsertion, yet maximize the amount of storage tape available.